I'm creating an image using MDT and it's going smoothly expect for one thing: any installers with prerequisites get overrun by the process and come back with 1618 errors (previous installation detected). For example, one of our programs uses SQL 2005 so once the installer starts, it starts installing the prerequisites and once they finish, the task sequence has assumed the entire installation is complete so it moves on, even though the program is not fully installed. I was thinking a way to solve this would be putting a timer between those applications that have prerequisites or I was thinking of having a script that installs the prerequisites separately (i.e. downloading each prerequisite individually and adding it into the application list.).

If you can get the individual installers for the prerequisite programs, what about adding those as applications to MDT. Then in the programs that require those prereqs, make those prereqs dependencies (right click the application and go to the Dependencies tab). You can even choose the order the dependencies are installed.